Carburetor for internal combustion engines



J. c. FEDERLE 1,828,800

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Oct. 27, 1931.

Filed Sept. 23. 1922 2 Sheets-Sheet l J. C. F EDERLE CARBURETOR FOR INTERNAL COMBUSTION ENGINES 2' Sheets-Shea 2 Filed Sept. 23. 1922 U MIIIr III/I I/i 1 Oct. 27, 1931.

Patented Oct. 27, 1931 UN TED TA ES PA ENToFFice..

' JosErH 1o. FEDEBLE, or DAYTON, onro, ASSIGNOR TO DELCQ-LIGHT COMPANY, or

DAYTON, OHIO, A CORPORATION"ornnLA Ann oAnBURETon FOR INTERNAL COMBUSTION; ENGINES 1 Application filed September 23,1922. Serial No. 590,002.

Thepresent invention relates to fuel sup- 3 ply systems for internal-combustion engines and moreparticularly for engines which are started automatically, and which, after being s-=started, drivea dynamo for electrical power purposes.

.One object of the invention 1s to prov de the engine with a fuel mixture which is r ch enough to facilitate .engine starting, and with 15 arelatively leaner mixture for running the engine. In this connection it is an object of the invention to gradually decrease therichness of the mixture during the starting operation so as to supply the engine with fuelof l-sucl1 richness as is necessary, while the engine warms up and finally attains operative speed.

A further object is to control the quant ty of the starting mixture in accordance with environment temperature to a certain extent whereby, if the engine is cold'when' started the amount of starting mixture available is greater than when the engine is warm. A further object of the invention is to provide an improved throttle valve which socooperates withthe venturi of the carburetor, and to construct and arrange the fuel jet that thefuel mixture proportions will be substantially constant over a wide range of engine speed.

A further object is to provide a throttle governor, preferably electrically"controlled,

which is substantially unafiected by the movement of fuel into the engine at 'high' 5 velocity.

A further object is to combine in a unitary structure devices for controlling the fuel following"description, reference being hadtothe accompanying drawings, wherein a preferred embodiment ofthe present invention is clearly shown.

In: the drawings:

bustion engine.

Fig. 1 is an end view of an internal com- Fig. 2 a. plan view-of the structure used inthe present invention.

. Fig.3 is a SGCtlOIliLlViGWOIl line 3 of Fig. 4 is a-sectionalview on the line 4-4 of Fig. 3. V

Fig. 5 is a perspective view of a portion of the engine throttle valve.

Fig. 6 is a sectional view on line 66 of Fig. 3.

Fig. 7 Fig. 3.

Fig. 8 is a sectionalview on line 88 of Referring to the drawings, 20 indicates an internal-combustion engine having an intake 21 whichis'controlled by a throttle valve 22 whichis. governed'electrically by means of a solenoid coil contained within a tube 170., This valve is constructed so that the governing action is not substantially impeded by the fuel mixture passing into the engine, as will be explained later. i The engine fuel system also includes an is a sectional view on line 7 -7 of 'electrical heating coil 25 for heating the fuel passing through the engine intake 21, to facilltate engine starting. A fuel reservoir 213 is provided into which fuel is pumped from a tank 200 by means'of a pump. The fuel then passes from the reservoir into a well 219 from thence into the engine through intake 21.

' Referring more in detail to the drawings, the engine intake 21-is connected with a carhuretor which comprises a frame 17 3. Frame 173 is provided with a pump cylinder 203 which has communication with an'inlet 202 pump plunger 205 provided with a'ball check valve controlled by a check valve 204. A

206'reciprocates within the cylinder 203, the

upper end of the plunger being connected at 207 with the lever 208 which is fulorumedat. 209 on a post 210. Lever 208 is connected by link 211'with an operatingpart of the engine preferably a rocker arm as disclosed 1918. As the engine operates fuelis drawn from" the tank 200 through a fuel delivery pipe 201 by means of'the pump and passes up through an opening 212 from the pump plunger 205 and into a reservoir 213. When the fuel has reached the lever 214 shown in Fig. 8 the excess fuel will flow over the overflow weir 215 and down the return pipe 216 to the tank 200. Therefore during the operation of the engine there is a substantially constant level of fuel in the carburetor reser- V011.

Now suppose the engine has remained idle for a considerable period, three hours for example, then all the fuel which was in the reservoir 213 will have made its way through a felt plug 217 and down through a passage 218 and into the initially rich well 219. The capacity of this well 219 is such that when all the fuel in reservoir 213 has passed into it, the levelof the fuel will be at the line 220. A disc 221 rests upon the plug 217 and pressure upon the plug is controlled by a screw 222 bearing against the disc 221 and having threaded engagement with bushing 223 which is threaded into the casting 173. A clip 224 engaging the head ofscrew 222 serves to revent accidental movement of this screw.

y adjusting the screw up and down the pressure on the felt plug 217 is regulated. Therefore the movement of the fuel from the reservoir 213 into the well 219 can be regulated so as to permit more fuel to reach the well 219 in cold weather than in warm weather in a predetermined length of time.

When the engine is started the suction thereof would cause fuel to be drawn up through the tube 225 from the well 219 and up through the nozzle 226 which is controlled by a needle valve 181. Air for the fuel mixture is drawn by the suction of the engine through the breather 230 which is constructed in accordance with the structure shown in the copending application of Lester S. Keilholtz and Ernest Dickey, Serial No. 390,247, filed June 19, 1920. For the present purposes it is sufficient to say that a mixture of fresh air and crank case fumes will be drawn through a passage 232 which includes the restriction 233 leadin past the nozzle 226 and into the passage 1 7. The flow into the passage 232 is controlled by disc valve 234 held upon its seat by means of a spring Rotation of the valve is affected by means of a handle 236 connected with valve shaft 237.

This fuel supply system is especially applicable to automatic lighting systems such as is illustrated in the copending application of Charles F. Kettering and Joseph C. Federle, Serial #589,991 filed Sept. 23, 1922, in which the starting of the engine is entirely automatic. In this type of system the fuel supply means is preferably constructed and arranged to provide an initially rich fuel mixture in order to facilitate engine starting. This initially rich mixture is not always supplied to the engine for the same length of time during the starting operation, but

the duration of the rich mixture depends on how long the engine has been stopped before starting again. F or example, ifthe engine has been stopped for example three hours or longer during which most of the engine heat due to its operation has been dissipated, then the initially rich mixture will be supplied to the engine for five minutes for example. if the engine has been stopped for only one hour before being started automatically some of the engine heat will still remain in the engine to assist in heating the fuel to volatilize same before starting therefore it will not be necessary to supply a rich mixture for a long time consequently the fuel supply means is arranged to supply the initially rich mixture for one third of the five minute period or one minute and forty seconds. In other words the duration of the supply of rich mixture is in proportion to the time the engine has remained idle up to a certain maximum period of idleness at the end of which the engine would be normally cooled off. Therefore it is apparent that the fuel supply means will supply this initially rich mixture in inverse proportion to the ability of the engine to heat the fuel to volatilize same.

The initially rich mixture is one which is richer in liquid fuel than the fuel mixture supplied during the normal running of the engine, but this rich mixture is not constant in proportion whereby for example the engine has remained idle for three hours the mixture will be richer than where the engine has remained idle for but one hour. Therefore the fuel supply means provides a starting mixturethe richness of which is inversely proportional to the ability of the engine 'to volatilize its own fuel.

The fuel supply means includes provisions for re ulating the supply of the initially rich mixture in accordance with environment temperature, for example, the engine will not cool off so rapidly in warm weather in cold weather, thereforethe quantity of an initially rich mixture to be supplied in warm weather will not be so great as would be necessary in cold weather.

After the engine has been idle for at least three hours the fuel in the well 219 will be at 220 and then when the engine is started the rate of fuel passing through the pipe 225 is greater than through the passage 218 therefore the level of fuel in the well 219 will drop down to the level 2 10. And as the fuel level falls through this distance the richness of this mixture will decrease. The capacity of the well 219 is more than sufficient to provide for engine starting in cold weather with the assistance of the heating coil 25 therefore the engine will normally be selfoperative long before the fuel has dropped to the level 240. In normal operation of the engine the starting will be accomplished in .extent,

reservoir 213 is full tooverflowing'the level iti'nthe we'll 219=will beiapproximately down -.to":the line 245. i

it. is desirable to withdraw fuel from well .219 downasinearto the. level 1240 as possible before any. more fuel is drawn intothis well in order 1 to maintain t the relatively low. level 1 of fuel in the well 219 which is required: for thet'running fuel mixture of the engine. Thereforethe means for siphoning fuel from --.the"rese1'voir213to the well 219.is. construct- -ed.so as to start action only after fuel in well .219: is down near the level 240, and so .as to ":that the level of "fuel in well 219 will be somewhere near, .the level 240. -.one.1eg ofthe .siphonis constructed so that the liquid level therein may lower arelativelimit the amount offuel being siphonedso ly great distance before-enough vacuum is I created to start siphoning, and their the fur- --,ther.lowering of the level a relatively short distance in "this leg will produce enough vacuunrtomaintain siphoning to the desired 'Thi's siphon comprisesa long leg or pipe 8 241 extending down to the level 247 where lit merges into an enlargement 248 which extends down 'below'the level 240', a branch or restricted passage 242-overthe top of ledge 243, and a short leg measured by the distance from ledge 243 "to the bottom of web'244. I

Asithe engine continues to operate the level in Well 219 will fall-down to the level240,

the fuel in the reservoir. The lowering of thefuel level in pipel24l will be slowed down relatively to the lowering of the fuel in well 219 because a vacuum is now being created in the passage 242 and pipe.241. But the pipe I 241 is so small 'that'siphoning will not take place when the level in well 219 starts to -fall below level 245. The level in the long siphon leg must first reach the level 246 before enough vacuum will be created to start the siphoning. As the internal diameter of the enlargement 248 is large relative to diameter ofpipe 241, the relative small drop in level from 247 to 246 will maintain the required siphoning action, that is overcome the'head ,offuel measured'by. the distance from ledge 242 to the fuel level in reservoir 213as it drops'f'rom level 214 to the bottom of web 244.

Therefore .If .the pipe 241 continued at the small -.-diameter down belowrthelevelx240,.the lowering of the 1 level 245" to $240 would not cre ate enoughtvacuum. in pipe :241 to: pull the fuel n over 'ithe; ledge .243: from the "reservoir I213, .as'this-level falls from 214 to. the lower edge tofixvebl244. Iftheenlargement 248 bemade toolong, then the. siphoning: will begin too soon and the fuel: in well.;2l-9aawill not reach the desiredi'low level dur' "githe'irunning'of the engine. Y Y 7 1 .By theitime the level in the long siphon leg has reached thee-level .246 there will :be enough vacuum created in'thepiper241 tto 1 produce siphoning andifueli will be siphoned fromtheireservoir 213 untilthe level in the 1-reservoir1213 drops i from' the line-.214 down to thellowerledge of the web.1244. Then the pipe 241 will be openedi'to atmosphere: and the fuel. in it will-seek the level :of. the fuel in 21 9 and'i-will raise". the level ofi fuel in well 219 from the level 240 to'the level 247; Therefore during. the operationofthe engine after ithas become self-operative the fuel level the well 218 will be somewhere betWeenthe levels 247 and 240. -The web244 extends be-,

low the level -214 "the [required distance Ito limit the. amount ofifuel siphoned, so that the lever. 247 will be buta. short distance above level: 240. Therefore fuel: mixture during en- :gine running willtend to "be uniform.

cThe siphoning a'ction described w ill "be somewhat? intermittent, but owing to the restricted passagefl242 the fuel pump will be 1 pcrn'iitted :to-"icatch up with the siphoning I action,'that is,- the siphoningwvilPbe retarded somewhat to permitthelevel to fall slowly from. 214'to the level uiiderxthe *webz244'and It will be noted that thetrrestrictedfpassage ,242 extends across the ledge 243but not down into: the reservoir 213 This constructionis to prevent ca'p'illarit-y being substantially effective along theweb 244. If capillarity was effective :at this placesiphoning would be nmore readily effective and all of the fuel pumped by the fuel pump would tend-to pass over into 'tl1e 'well219 as fast as the pump 7 would dliver'fuel to the reservoir been idle for an hour,'the.fuel level in theres- -ervoir 213 is belowthe Web 244 and therefore "the passage 242 is notsealed, and theEfueI in; the Well 219 has only raised to approximately I. x1125 The'advanta ge ofrforegoing siphoning is apparent when for'example,"the'plant has one third of the maximum height. Then, as

the fuel falls in the well 219 when the engine is again operated, by the time the level in reservoir 213 has been raised to seal the passage 242 the levelof the fuel in the well 219 will be down to approximately at 247. However as soon as the level in the siphon leg falls below the level 247 the vacuum in said siphon leg will be increased quickl due to the large diameter of the member 2 8. In this manner as is quite evident the fuel in the pipe 241 does not initially have to be high to provide the required vacuum, when receding, for siphonmg over the fuel.

It is apparent from the foregoing that the engine has been supplied with a starting mixture the richnessof which will vary according to the level in the well 219 at the time the starting of the engine is initiated. The dura tion of the supply of the starting mixture Wlll depend also on the level of the fuel in the well within the tube 170 mounted on-the bracket 171 which is attached by means of screws 172 to the engine carburetor frame 17 3. The solenoid armature is attached-by a rod 174 to an arm 175 which is attached to a shaft 17 6 supported by the bracket 171. The shaft 17 6 is formed preferably integrally with the rotatable throttle valve 22 which may be said to include a cylindrical barrel which has been nearly revered by means of a cylindrical cutting tool positioned with its shaft at right angles to the shaft 176 and having such a diameter that the distance 177a (see Fig. is substantially equal to the diameter of the fuel intake passage 177 leading out from the carburetor casting 173 and through the head 178 of an engine cylinder 179. The valve 22 is provided with a notch 180 in order to provide clearance for the needle valve 181 which is carried by an adjusting screw 182 threaded into bushing 183 which is screw threaded into the casting 173. A clip 184 is supported by the casting 173 to prevent accidental rotation of the screw 182 due to vibration of the engine.

A stub shaft 185 is found. on the side of the valve 22 and acts as a continuation of the shaft 176. Shaft 185 is rotatably mounted within a socket in the frame 173 and acts as a hub for the valve 22. Suitable clearance is provided between the cylindrical portion of valve 22 and the frame 173 so that the valve -1nay rotate freely. Air passing through the passage 232 and past the valve 22 would have a tendency to cause the valve to bind within its seat and cause the valve shaft 17 6 to bind within its bearing if the stub shaft 185 were not provided. However, with the stub shaft 185 the valve 22 is permitted to rotate free'from binding, and therefore the governing action can take place substantially unimpeded.

It will be noted that the throttle valve 22 co-operates with the restriction 233 of passage 232 to provide a variable Venturi passage as the position of the valve 22 is varied by the action of the electric throttle governor. By varying the Venturi effect as the throttle is opened or closed it has been found that the n'oportions of the fuel air mixture passing through the passage 177 will remain substantially constant for varying throttle openings. In controlling the fuel mixture proportion, the relation of the nozzle 226 to the throttle 22 is important. It has been found that this nozzle should be located as in Fig. 6 close to the edge of the notch 180. It has been found satisfactory when the axis of the nozzle 226 is substantially tangent to the periphery of drum of metal of valve 22.

The heating coil for the intake is preferaly contained within a refractory and nonconducting tube 190 located within the passage 177 and the terminals of the coil 25 are supported by non-conducting bushing 192 and 193 which are screw threaded into the casting 173.

It will be apparent from the foregoing description that a unitary structure is provided which includes the engine carburetor, a variable mixture fuel supply system, a pump for delivering the fuel to the system, an automatic throttle governor and a fuel heating element. This unitary structure is readily attached to the engine by means of screws 186. Access may be easily had to the various parts. By merely removing the needle valve 181 and then the bracket 171 the valve 22 is readily removable. The well 219 being a separate casting from thatof the frame 173 can be removed by removing screws 187 and the pipes 225 and 241 laid bare. In order that dirt and dust will not collect in the reservoir 213 a removable cover 188 is provided having an extended portion 188a which may be used as a handle for swinging the cover about its pivot 189. With the cover swung out of position the attendant can observe the length of time required for While the form of mechanism herein shown 1 and described constitutes a preferred embodiment of one form of invention, it is to be understood that other forms might be adopted and variouschanges and alteratlons made in the shape, size, and proportion of the ele n ments therein without departing from the spirit and scope of the invention;

VVh-at .is claimed is as follows: e

1. A charge forming device for-an internal combustion engine comprising in combination a reservoir for containing fuel; a well for receiving fuel from said reservoir; a member having a Venturi'passage adapted to be connected with an engine intake; a nozzle for conducting fuel'from the well to the Venturi passage; means permitting fuel to gravitate from the reservoir to the well whereby to accumulate a height of fuelin said well desirable for an initially rich mixture; and suction controlled means rendered operative when said height of fuel has been materially reduced for withdrawing fuel from said reservoir in amounts such as to maintain a substantially constant fuel level in the well during engine running.

2. A chargeforming device for an internal combustion engine comprising in combination a reservoir; means for supplying fuel to the reservoir; a member having a Venturi passage leading to the engine; a well for receiving fuel from the reservoir; a nozzle for conducting fuel from the well to the Ventur1 passage; suction controlled means for withdrawing fuel from the reservoir to the Well in amounts such as to provide a relatively constant fuel level in the well during engine running; and means allowing fuel to gravitate from the reservoir to the well during engine idleness.

3'. A charge forming device for an internal combustion engine; a 1 unitary structure comprising a fuel reservoir, a fuel pump for supplying the reservoir from a fuel source, afuel well connected with" said reservoir, engine suction respo-nsive means for supplying fuel from the reservoir to the-well, means permitting fuel to gravitate from the reservoir to the well, and-fuel airmixing provisions'in communication with said well and adapted to be connected with an engine.

4:. A charge forming device for an internal combustion engine comprising in combination a reservoir for containing'fuel; a well located beneath and'adapted to receive fuel from said reservoir; a mixture supply passage through'which a combustible mixture may flow to an engine; a nozzle in communication with the interioraof said-well, and

which nozzle discharges into the mixture passage aforesald; a permanently open passage through which fuel may flow by gravity from said reservoir to said well; aporous member associated withsaid passage and adapted to control the flow of fuel Itherethrough at a rate such that the amount of fuel supplied to said well is insufficient to's'upply the normal demand for the engine; and suction controlled meansfor causing fuel to flow from said reservoir into said Well." v

' 5. A charge forming device for an internal combustion engine, comprising in combinae tion with a fuel and air mixing chamber adapted to be connectedwithan engine; of a fuel well; conduit meansrfor conducting fueLfrom the well: to .themixing. chamber;

means for maintaining .a low level of fuel in a fuel well; vconduit means for conducting fuel from the well to the mixing chamber; means for maintaininga low level of fuel in the well for normal engine operation; and means for supplying fuel to the well during the engine idleperiod at a ratesubstantially in proportionto the cooling of the engine to provide a higher level of fuel in the engine for starting purpose, the-size of the well being such that thequantity of fuel between said higher level and said normallow -le,vel is sufficient for operating the engine while said engine isbeing heated to eflicient operating temperature.

7'. A charge forming device for an internal combu'stion'eng'ine, comprising in combination with a fuel and air mixing chamber adapted to be connected with an engine;'or a fuel Well; conduit means for conducting fuel from the well tothe mixing chamber; means for regulating the 'flow of-fuel to the well whereby the level in said well gradually falls during engine operation"; and other means for regulating the flow of fuel to said well after the level in said well reachesa predetermined low point to maintain the level substantially at said' point duringpthe operationof the-engine.

' 8. A charge forming device for an internal combustion engine, comprising in combination with a fuel [and air mixing chamber adapted to be connected with an engine; a fuel 'reservoir; awell below said reservoir for receiving fuel from the reservoir"; conduit means for delivering fuel fromthewell to the .mi'xingf chamber; means for regulating the flow of fuel from the reservoir tothe well I whereby the fuel level in saidwellfgradually falls during engine operation; and a'siphon rendered operative after the le'vel'f in said wells reaches a certain point for delivering fuel from the reservoir to the well and' for maintaining the level substantially at'said point during the operation :ofthe engine.

9. A charge forming device for an internal combustion engine, comprising in combine tion a fuel and air mixing chamber adapted to be connected with an engine; a fuel well; conduit means for delivering fuel from the well to the mixing chamber; and means providing starting and running levels of fuel in said well, the size of the well being such that the quantity of fuel between said levels is suflicient to operate the engine until the engine temperature increases to the normal operating point.

10. A charge forming device for an internal combustion engine, comprising in combination a fuel and air mixing chamber adapted to beconnected with an engine; a fuel well; conduit means for delivering fuel from the well to the mixing chamber; means providing starting andrunning levels of fuel in said well, the size of the well being such thatthe quantity of fuel between said levels is sufficient to operate the engine until the engine temperature increases to the normal operating point; and means for delivering fuel to the well during the idle period of the engine at a rate substantially in proportion to the cooling of the engine.

11. A charge forming device for an internal combustion engine, comprising in combination a fuel and air mixing chamber adapted to be connected with an engine; a fuel well; conduit means for delivering fuel from the well to the mixing chamber means providing a high starting level of fuel in said well; means providing a low running level of fuel in said well, the size of the well being such that the quantity of fuel between said levels is suflicient to operate the engine until the engine temperature increases to the normal operatingpoint.

. 12. A charge forming device for an internal combustion engine comprising, in com; bination, a fuel and air mixing chamber, a source of fuel supply for normal engine operation connected with said chamber, means for providing during the idle period of the engine a quantity of auxilary fuel sufficient to enrich the mixture throughout the warm ing up period of engine operation.

13. A charge forming device for an internal combustion engine comprising, in combination, a fuel and air mixing chamber, a source of fuel supply for a normal engine operation connected with said chamber,

means for providing during the idle period of the engine a higher level of fuel in the source and of such quantity for providing enriched mixture throughout the warming up period of engine operation.

14. The method of gradually changing the fuel mixture proportions, to be delivered to an internal combustion engine, at a rate that V proper fuel mixtures are created from the time of starting as a cold engine through'the warming up period of engine operation, which method consists in supplying air and supplying fuel at a certain pressure for creatproper fuel mixtures are created from the time of starting as a cold engine through the warming up period of engine operation,

which method consists in supplying air and supplying fuel at a certain pressure for creating a fuel mixture for a cold engine, and then gradually diminishing the pressure on the fuel during the warming up period of engine operation.

16. The method of forming a charge for an internal combustion engine for starting purposes and gradually changing the relative quantity of fuel and airof such charge at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through'the warming up period of engine operation and maintaining the proper fuel mixture proportion for the engine when operating at normal temperature, which method. consists in establishing a certain pressureon the fuel and supplying fuel under such pressure and supplying air to the engine, gradually changing the pressure on the fuel during the warming up period of engine operation, and then maintaining a substantially constant pressure on the fuel.

17. The method of forming a charge for an internal combustion engine for starting purposes and gradually changing the relative quantity of fuel and air of such charge at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through the Warming up period of engine operation and maintaining the proper fuel mixture proportion for the engine when operating at normal temperature, which method consists in establishing a certain pressure on the fuel and supplying fuel under such pressure and supplying air to the engine, gradually diminishing the pressure on the fuel during the warming up period of engine operation, and then maintaining a substantially constant pressure on the fuel.

18. The method of gradually changing'the relative quantity of liquid fuel and air of a fuel charge to an internal combustion engine, at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through the warming up pe riod of engine operation, which method consists in establishing a certain hydrostatic head o'fthe liquid fuel, delivering fuel from such supply and air to the engine, and then gradually changing the hydrostatic head of the liquid fuel during the warming up period of engine operation;

19. The method of gradually changing the relative quantity of liquid fuel and air of fuel charge to an internal combustion engine,

at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through the Warming up period of engine operation, Which method consists in establishing a certain hydrostatic head of the liquid fuel, delivering fuel from such supply and air to the engine, and then gradually lowering the hydrostaticjhead of the liquid fuel during the warming up period of engine operation.

20. The method of forming a charge for an internal combustion engine for starting purposes and gradually changing the relative quantity of liquid fuel and air of such charge at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through the Warming up'period of engine operation and maintaining the' proper fuel mixture proportion for the engine When operating at normaltemperature, which method consists in establishing a certain hydrostatic head of the liquid fuel, delivering fuel from such supply and air to the engine, v gradually changing the hydrostatic head of 7 the liquid fuel during the Warming up period of engine operation, and then maintaining a substantially constant hydrostatic head of the v liquid fuel.

21. The method of forminga charge for an v i internal combustion engine for starting purposes and gradually changing the relative quantity of liquid fuel and air of such charge at a rate that proper fuel mixture proportions are created from the time of starting as a cold engine through the Warming up period of engine operation and maintaining the proper-fuel mixtureproportion for the engine when operating at a normal temperature, which method consists in establishing a certain hydrostatic head of the liquid fuel, delivering fuel from suchsupply and air to the engine, gradually diminishing the hydrostatic head of the liquid fuel during the warming up period of engine operation, and then maintaining a substantially constant hydrostatic head of the liquid'fue'l.

In testimony whereof I hereto'aflix my signature.

JOSEPH o. FEDER-LEQ 

